SMR No.: ME019-030001-
Monument Type: Megalithic Art
1 of 43 orthostats on the right side of the east megalithic passage tomb chamber at Knowth, Brú na Bóinne. The orthostat is decorated with three large interlinked concentric circles and a series of large and small chevrons.
Note: Orthostat has been rotataed onto side by 90° to ensure maximum rendering size
3D Capture Method: Close range Scanning
3D Capture Description: The Artec EVA scanner is used to generate high resolution models of surfaces with small scale detail. The Artec EVA uses structured light to record. A forensics tent is used to create a controlled lighting environment and ensure measurement can proceed regardless of the weather when used outdoors. Scanning is undertaken with the fastest speed setting (15 frames per second) and with a minimum 400 mm depth of field. The data is recorded with sufficient overlap between scans to ensure easy registration.
- Resolution 0.5 mm
- Accuracy 0.1 mm
- Accuracy over distance 0.03% over 100 cm
- Texture Resolution 1.3 mp
- Colours 24 bpp
- Light Source flash bulb (no laser)
- Video frame rate 16 fps Exposure time 0.0002 s
Post-processing is done in Artec Studio 9 software: individual scans are edited, aligned, before a final surface is generated using global registration, fusion, and a small objects filter algorithm. If required, a textured surface can also be created. The model is exported from Artec Studio 9 as an .obj file. For dissemination purposes a 3D pdf of the model is generated using Geomagic Studio 2012.
Data Processing Software: Artec Studio 9 & Geomagic Studio